Finally understood the reason of this issue, according to UiPath support the minimum version of on-premise Orchestrator and Action center that supports ‘Forward task’ and ‘Complete Task’ activities is 21.4, and in my case it was 20.10
Anil_G
ashokkarale
jinal.shah
Gautham_Pattabiraman
postwick
chandreshsinh.jadeja
vrdabberu
Ajay_Mishra
sven.wullum1
Vyshnavi_Nalumachu